Guiding means for liquids and gases



4 Sheets-Sheet l A. J. SCHNEIDER GUIDING MEANS FOR LIQUIDS AND GASESINVENTOR.

am A! I *1 July 13, 1954 Filed Feb. 26, 1948 A. J. SCHNEIDER 2,683,419

GUIDING MEANS FOR LIQUIDS AND GASES .4 Sheets-Sheet 2 Will II July 13,1954 Filed Feb. 26, 1948 INVENTOR. WMJM BY d- July 13, 1954 A. J,SCHNEIDER GUIDING MEANS FOR LIQUIDS AND GASES Filed Feb. 26, 1948 V 4Sheets-Sheet 4 INVENTOR.

Patented July 13, 1954 UNITED STATES PATENT OFFICE assignor to Socitfinanciere dExpansion Commerciale ct Industrielle S. A. Sfindex,

Sarnen, Switzerland Application February 26, 1948, Serial No. 11,157 InSwitzerland April 16, 1946 Section 1, Public Law 690, August 8, 1946Patent expires April 16, 1966 4 Claims.

This invention relates to a novel guiding means for liquids and gases orfor mixtures thereof with particles of matter carried along thereby.

The means in question serves to produce, or to guide, annular flow, inparticular in centrifugal machines such as hydraulic turbines, pumps,gas turbines, fans, centrifuges, and the like.

The requirements which must be met by the guiding means employed in theconstruction of centrifugal machines are manifold, and they must be suchas to guide a flow with a predetermined tangential component along asolid of revolution.

They must in addition form or produce a uniform flow with full admissionabout the entire circumference and if necessary convert potential energyinto kinetic energy and vice versa. In addition, it must be possible tovary by means of regulating means the admission and the area ofthrough-flow while maintaining the angle of flow constant, and incertain cases it must be possible to vary at will the tangentialcomponent of the flow, hereinafter referred to as the twist, by means offurther regulating means which are separately applied.

With the known guiding means, there is no satisfactory method offulfilling these requirements simultaneously, and in addition existingconstructions (for example adjustable guide vanes and the like) havestill further constructional disadvantages, such as the multiplicity ofthe parts to be moved by regulating means, difficulty of packing guidemeans, which are to be actuated by regulating devices, and the clearancelosses thereof, compromise by limitation of the number of blades, andthe like. Owing to the aforesaid disadvantages, it has hitherto beenimpossible'to produce an impulse turbine with full admission about theentire circumference instead of the pelton turbine with its partialadmission, in spite of the fact that a further field of application wasopen tothe impulse turbine with complete admission, by reason of itshigher speeds due to the reduced size of the rotor and by reason of itscompact construction for maximum unit outputs, and also by reason of itssimple design with high efficiency over all ranges of operation, atvarying loads and pressure drops.

By reason of this fact, various attempts have also been made to provideguide means not having the'aforesaid disadvantages. In particular,annular slide valves have been proposed with which a varying area ofthrough-flow was produced by the axial displacement of a slide valve.

It was desired to p'roducethe' tangential flow bya annular flow on theother side, and

the spiral inflow from the spiral casing, and by means of spirallycurved guide blades with parallel axes, which were disposed directly infront of the slide valves, in the path of the inflow. These proposals,however, did not produce the desired constant twist over the entirecircumference and for all opening positions, owing to the fact that atthe moment when the annular slide valve commences to open a moremeridional outflow occurs, instead of the outflow with a predeterminedtangential component, at all places where no spiral guide surface issituated.

Only when the annular slide valve is fully open will the tangentialcomponent also reach its complete uniform degree.

The regulatability of the area of the annular flow with full admissionover its entire circumference and constancy of the desired twist isproduced with the guide means according to the present invention by thefollowing three elements:

(1) A material surface of revolution limiting the annular flow on oneside,

(2) A second surface of revolution limiting the (3) A spiral surface,with at least one thread, which guides the annular flow and which mustbe imagined as having been formed by the spiral movement of a line witha pitch ranging from a value equal to or greater than zero up toinfinity, inclusive, at least one of the said elements, being adapted tobe screwed with respect to the other with a spiral movement equal tothat referred to above for the purpose of carrying out an adjustingmovement. The desired variation of the area of throughflow for thepurpose of varying the admission or the quantity of the fluid flowingthrough is preferably obtained by screwing the two flow limitingsurfaces with respect to one another.

Independently thereof, a variation of the angles of flow can beachieved, as will later be described:

(a) By a displacement, defined in (3) with a spiral movement of thespiral flow-guiding surface with respect to the two flow-limitingsurfaces, whereby it is possible to vary the mean diameter of the inletand outlet edges of these surfaces,

(1)) By variation of the area of through-flow between the twoflow-limiting surfaces at a certain distance outside the area of thespiral flowguiding surface.

Fig. 1 is a vertical central section of a first embodiment;

Fig. 2 is a vertical central section of a part of a second embodiment;

Fig. 3 is a vertical central section of a further embodiment;

Fi 4 is a vertical central section of a turbine having guiding meansaccording to the invention;

Fig. 4a is a section at right angles to the axial section shown in Fig.4, and

Fig. 4b is a section along line IV-IV in Fig. 4a.

Fig. 5 shows the velocity triangles of the embodiment of Fig. 4, and

Fig. 6 is a vertical central section ofa Kaplan turbine provided withguiding means according to the invention.

In Figure 1, numerals l, 2, and 2" respectively refer to the outer andinner flow-limiting surfaces in section, the area of through-flowvarying with the variation of the position of 2 in the direction of thedouble arrow. In Fig. 1, 3 designates in cross section a multi-threadedspiral surface determining the direction of flow and in particular therotational component. In place of a multi-threaded spiral surface also asingle threaded spiral surface could be provided. According torequirement, it is also possible to make only the part 2 movable, whileits extension 2" may be rigidly connected to the remaining part of theguiding means. The forward edges of 2 and 2" would then coincide at fullopening. Thev pitch of the spiral surface and its profile need only beconstant insofar as this is necessar with a View to obtaining a constantoutlet angle and with a view to the screwing of part 2 with respect to,part 3, while it may gradually change to infinite outside of part 2,that is to say within the range of 2 The flow leaving freely in thedirection of the arrow 4 has the form of a hyperboloid, the generatricesof which constitute the rectilinear discharge jets. When the guidingmeans shown in Figure 1 is traversed in the opposite direction to thearrow 4, it acts as a diffuser with the flow directed outwardly from thecentral axis, that is to say for converting velocity into pressureenergy.

By accordingly interchanging land 2 (Figure 1) with respect to thecentral axis, the inwardly directed annular nozzle is converted into anoutwardly directed annular nozzle, and by reversal of the direction ofthe arrow 4 it is converted into an inwardly directed diffuser.

While part 2 (Figure 1) determines the area of. through-flow at theoutlet from the space containin the flow-guiding surfaces, that is tosay where the exact outlet angle, or the tangential component thereof,is still determined by the presence of the flow-guiding surfaces, thearea of through-flow can be narrowed at a certain distance outside thespace containing the flowguiding surface by an additional controlmember.

By such a reduction in the area of through-' flow, the direction of flowis deflected towards the meridian plane and consequently the tangentialcomponent, that is to sa the twist can be reduced.

Such a control member for adjusting the tan gential component in theoutlet from the annular flow, is constituted by the annular slide valve5, or 5' in Figure 1. Upon the complete withdrawal of valves 5 and 5',or upon complete freeing of the area of through-flow, the angle of outflow determined by the spiral surface is obtained, and the flow retainsthe maximum tangential'component determined by the spiral surface.

If, on the other hand, valve 5" is first moved forward towards the flowissuing from the outlet and the said fiow is then further narrowed bymeans of valve 5, the filaments of the stream will be diverted in themeridional direction in the degree in which the area is reduced by valve5.

In the extreme case, directly before the closing of the annular outletaperture by the control valve member 5, the tangential component of thefilaments will become zero and will be a meridional out flow.

The carrying out of this regulation in two stagesby means of controlvalves 5 and 5 is not necessary, but with this method a certain impactloss when the "marginal jets impinge upon valve 5 can be avoided owingto this slight rounding-of the control edge of valve 5 at the point oftransition into valve 5.

The regulating movements of the annular slide valves 5. 5 and 2 may, forinstance, be efiected ina mechanical manner as is shown in Fig. 1. Tothat end the annular slide 2 and the valve 5 are each provided with arim 6 and l. The toothed rim 6- is in mesh with a toothed wheel 8 andthe rim '1 is in mesh with a screw wheel 9. Wheel 8 can be turnedbymeans of the hand wheel I0 and screw wheel 9 by means of the hand wheell2 and the spindle H. If it is desired to vary the through-flow areathrough the nozzle the annular slide 2 may be simultaneously displacedtogether with the annular valves 5 and 5' by rotating the toothed wheels8 and the screw wheel 9. Rotation of the wheels 8 and 9 by the sameangular extent causes the same axialdisplacement of the annular slide 2and valve 5. The toothed wheel 8 is rigidly connected with the spindle Hand thereb with the screw wheel 9 by means of the clamping device [3.The annular slide 2 is prevented against turning relative to slide valve5' and the latter relative to slide 5' by the splines I6, which,however, permit axial displacements of said slides. If the tangentialcomponent has to be altered, the slide 2 has to be displaced relativelyto slides 5 and 5' respectively, to which end the clamping device [3 isloosened and the screw wheel 8 only is turned by the hand wheel H], thehand wheel l2 being kept stationary. The above described dependencybetween the movements of slide 5 and slide 5 is automatically obtainedby a pressure spring Hi and the two abutments i and [5' provided in theslides 5 and 5' respectively. As long as the slide 5 is positionedagainst the liquid stream a clearance is present between the abutmentsl5 and I5 and the spring M will maintain the slide 5' in its foremostposition. Only when the slide 5 is completely withdrawn from the liquidstream the abutment l5 and the slide 5' is also withdrawn from theliquid stream thereby overcoming the force'of the spring hi.

Figure 2 shows, by way of example, an arrangement of such an annularnozzle" having an inwardly directed flow without any substantial axialcomponent at the outlet. The principle of the arrangement is the sameasin. Fig. 1 Numeral ll designates the first surface of revolution, andnumeral 18 the second surface of revolution having helical slots, andbeing adjustable with a hand wheel-by screwing it on the helicalsurfaces [9. The variation of the throughfiow is achieved by thevariationof the outlet area caused by the rotation of the flowlimitingsurface [5 (which has the shape of a screw). on the helicalsurface I9.

The radial extensions l1 and I8, shown in chain lines, of theguidesurfaces l? and i3 limiting the fiow. render possible by means not showna small scale-reduction of the outlet area outside the-range oftheflow-guiding surfaces.

These radial extensions may be made of elastic material and canconsequently have, within certain limits, a similar function to thecontrol members 5, of Figure l.

A combination of inward and outward flow with respect to the centralaxis isshown in Figure 3, in which 20 and 29 are fixed flow limitingsurfaces, while the surfaces 2| and 2| to be adjusted are assembled in awedgeshaped annular body with spiral slots for the passage of thehelical surfaces 22 and 22', which are assembled on the fixed flowlimiting surfaces 26 and 20'. The regulation of the through-ilow isachieved by a screwing displacement of the body 2l-2l'.

This construction renders unnecessary any packing between the flowlimiting surfaces 2| and the spiral surface 22, and also between theparts 2| and 2| of Figure 3, even at high pressures. A disadvantage ofthis construction, on the other hand, is the higher outlet loss and thesomewhat greater danger of obstruction, owing to the dividedthrough-flow aperture.

The angles of the two guide surfaces 20 and 21 must so correspond tothose of surfaces 20 and 2| that the confluence of the two annularstreams takes place at equal angles that is to say without losses.

Figure 4 shows an embodiment of the combined application of the abovedescribed annular flow guide means. It shows, by way of example, aturbine which is theoretically adjustable without losses for anyadmission from zero to maximum, and for any variations in pressure drop,suitably modified, the design is also applicable to a pump. In thisfigure, 3| is the inlet distributor of the turbine of a similar designto the annular nozzle, Figure 1.

In contrast to Figure 1, the control edge 62, which is alreadyassociated with the rotating rotor, here has the same function as thecontrol member 5 in Figure l. The opening which is freed both by thecontrol edge 62 and by the control member 6|, determines the area ofthroughfiow and consequently the admission to the rotor and to theturbine. The rotating rotor consists of the shaft 69, the hub 31, theactual rotor 38 and the control member 65. The rotor comprises at 63 anannular diffuser and at 64 an annular nozzle the opening of which isregulated by the v control member 65, as also by the control edge 68,from the non-rotating suction pipe inlet. The

spiral surfaces 63 of the annular diffuser and 64 of the annular nozzleof the runner wheel are here illustrated for the sake of simplicity withI an infinite pitch, as simple radial surfaces. The relative velocity atthe inlet into the runner wheel, as also the relative outlet velocityfrom the runner wheel will accordingly be purely meridional. By thegeometrical addition of the meridional directed relative outlet velocityfrom the runner wheel with its circumferential component, there is setup in this case a certain twist at the inlet into the suction pipe. Thistwist flow will theoretically be converted without losses into an axialflow in the manner of an annular diffuser by a slender spiral surface inthe suction pipe which gradually merges into an infinite spiral pitch.

If it is now desired to adjust the opening of the turbine, the entirerotor is to be displaced in the axial direction. Thereby the area ofthrough flow of the distributor and also the area of through flow of therunner wheel will simultaneously be adjusted with strict geometricalaccuracy without altering any of the angles of flow, that is to saywithout thereby having to allow for any impact losses at the inlet intothe runner wheel and in the suction pipe of the turbine. The axialdisplacement of the rotor may be effected hydraulically for example asshown in Fig. 4 by regulating the static pressure present in the spaceabove the cover 24 and below the runner, respectively, by a regulatingmovement of the valve piston 34 in accordance with the desired admissionof the turbine or by means of impulse blades operated by the annularfiow itself. Furthermore the impulse for moving the valve piston may bederived from a speed governor or from a float.

The aforementioned displacement of the annular slide 5! relative to thecontrol edge 62 may be automatically effected by hydraulic means as isshown in Figs. 4a and 4b. Fig. 4a is a section at right angles to theaxial section shown in Fig. 4 and Fig. 4b is a section along line IVIVin Fig. 401.. If, as mentioned above, an impact loss occurs in front orthe forward side of the blades 63, the pressure immediately in front ofa blade is higher than that at the rear of a blade. This pressuredifference is used as an impulse for the hydraulic regulation. The pipe25 (Fig. 4b) derives the pressure from in front of a blade at 59 whereasthe pipe 26 derives the pressure immediately at the rear of a blade.

The surplus pressure in front of the blades is conducted into one end ofthe cylinder 21 having a valve piston 28, whereas the lower pressure atthe rear of the respective blade is conducted to the other end of thecylinder 21. The piston 28 will therefore move in the downward directionlooking at Fig. 4b; the pipe 44 is connected by way of the pipe 29 withthe suction pipe and the pipe 42 is connected by way of the pipe 30 withthe pressure chamber above the runner. The high-pressure in pipe 42 isconducted, as is shown in Fig. la into the annular chamber 4! (Fig. 4),while the suction pipe pressure in the pipe 44 gets in a similar mannerinto the annular chamber 4-3 (Fig. 4). The surplus excessive pressure inthe chamber 4! over that in chamber 43 causes a displacement of theannular body 6! in the upward direction towards the control edge 62until after the pressure difference in front and at the rear of theentrance of the runner blade is compensated.

The automatic displacement of the annular slide 65 (Fig. i) may, forinstance be effected by the influence of the pressure diiferenceimmediately in front and at the rear of the spiral surfaces 40. By atwo-fold system of bores on the body 5'! the upper annular chamber isdirectly connected with the point 32 immediately in front of the spiralsurface for obtaining an impulse and the lower annular chamber23 isconnected with the point 33 immediately behind the spiral surface. Asthis system of bores could only be'shown in dotted lines it has alsobeen turned into the plane of section and shown in chain-dotted lines inthe left half of Fig. 4.

.In order to obtain a correct regulation with while'the speed ofrotation of the rotor would fact that the velocity and consequently alsothe circumferential component Cu is increased by reduction of the areaof through-flow between the spiral surfaces and that owing to the factthat cum lc, this increase is maintained during the passage past thecontrol edge 62' in spite of the fact that the total velocity is not atthe same time increased.

At the same time, the relative velocity of flow from the runner wheelinto the suction pipe will be reduced owing to the reduction of thepressure. In order nevertheless to avoid impact losses at the inlet intothe spiral surfaces of the suction pipe, the tangential component in therunner wheel outlet must be increased, that is to say, the controlmember 55 is here also moved nearer to the control edge $8 automaticallyby the turbine and the desired freedom from impact losses in-the suctionpipe is againestablished for the new pressure drop. Consequently, withthis type of turbine both an alterationin the degree of admissionwithout impact losses and also theoretically loss-free allowance forfluctuationin pressure drop are for the first time rendered possible bya completely satisfactory guiding of water from the strictlygeometrically and hydraulic points of view.

Figure shows the velocity triangles associated with Figure 4. Thisfigure may be considered as a covering sheet to Figure 4. It will beassumed that 01 (or 01 in this projection) is the outlet velocity forthe point T1 or T1 (Figure 4 and Figure 5) at the outlet from the rangeof the spiral surfaces of the distributor. It coincides in directionwith the tangent to the filament passing through T1. This filament isidentical to the line of intersection of the conical'fiowlimitingsurface with the spiral flow-guiding surface. ThllS,-Cl' in Figure 5represents-the elevational projection of the outlet velocity as atangent to this line of intersection L. (All references-provided with adash represent elevation projection, while all velocity vectorreferences having a dash refer to the fact that they are shown in theirtrue value in this projection.) If new the point T1 is rotated through90 about the axis of the cone with the apex S1, the point T1" isobtained with the corresponding velocity vectors c1 ponent and or" themeridiona1 component Clm in. its true value.

The velocity diagram for the point T2 can simply be calculated fromthese values:

Since the same quantity of water can flow through all the annular areas,the radial component for the point T2 (Figure 4) is calculated from thatof the point T1 by the equation:

representing the contraction factor due to the control edge 11.

A further equation is given by the following and on constituting theradial com 8 Where h is the axial distance between T and control member61. hg is the axial distance between T and control member 62.

is the contraction of the trough-flow area from T and r are the radii atthe points T and T c is the circumferential component of the absolutevelocity 0;

k is a constant 11/2 u are'circumferential speeds at the points T and TThe velocity-vectors for point T2 are obtained therefrom in the drawing.

Again the velocity factors'for the point T3 (Figure 4) are shown by thecondition that the radial components are inversely proportional to thethroughfiow areas, that is to say,

0 ,1 c m contraction factor (The contraction factor, given by theposition of 6! with respect to $5 in Figure is shown as equal to one inthe drawing.)

Further, the direction of the filaments of the stream, or the directionof the velocity vector ws, is given so that the velocity. triangle forthe point T3 in Figure 4' could be drawn. The vectors for the point T4were drawn from T3 (Figure 4) in exactly the same way as for thedetermination of the vectors for the point T2 from T1.

Figure 6 shows the application of the principle of the invention to theguide wheel of 2. Kaplan turbine. This afiords the advantage of simplerdesign as compared with the use of adjustable guide vanes, and a verygood steady delivery to the Kaplan propeller. As in the above describedfigures, the flow limiting surfaces ll, l2 and the flow guiding surfacel3; represent again the main parts of an annular flow nozzle. Theregulation of the admission is again eiiected by the one flow limitingsurface 12 relatively to the flow guiding surface 13. This screwing. maybe obtained by toothed rim [4, toothed wheel 15, bevel drive it and handwheel 1'! as shown.

By the use of this guiding means the constancy of the twist withdifferent degrees of admission is, however, lost for geometricalreasons, but it can be compensated for by the adjustability of theKaplan blades. It isknown that by this adjustability of the Kaplanblades a compromise is obtained between avoiding as much as possibleimpact losses at the entrance side of the runner blades and"twist lossesin the suction pipe.

By the possibility of converting the kinetic energy of the twist in thesuction pipe, the Kaplan runner can be set to be entirely free of lossesat the entrance side and the"twist remaining at varying admission andhead can be converted free of losses.

I claim:

1. Guiding'means for annular flow in rotary machines, comprising, incombination nested bodies" providing a pair of coaxial surfaces ofrevolution for limiting said annular flow, means providing a helicalsurface having at least one threaddisposed between said surfaces ofrevolution in helically adjustable engagement with one of said bodiesand secured to the other of said bodies and'adapted to guide the annularflow, said limiting surfaces being provided with portions extendingparallel to each other and approximately over the distance between twoadjacent helical surfaces, said helical adjustment comprising helicalslots on one of said flow limiting surfaces engagingly cooperating withsaid helical surface, means for axially displacing said one flowlimiting surface by screwing it relatively to said helical surface forefiecting a controlling action to regulate the quantity of the throughflow, and packing cups provided adjacent to said helical slots.

2. Guiding means for annular flow in rotary machines comprising incombination nested bodies providing a pair of coaxial surfaces ofrevolution for limiting said annular flow, means providing a helicalsurface having at least one thread disposed between said surfaces ofrevolution in helically adjustable engagement with one of said bodiesand secured to the other of said bodies and adapted to guide the annularflow, said helical surface being arranged in a zone of a relativelylarge diameter in which the guided flow has low velocities, to whichzone a further zone of guided flow at high velocities joins which isfree of helical surfaces, and means for axially adjusting one of saidflow limiting surfaces relatively to the other by screwing it on saidhelical surface to regulate the quantity of the through flow.

3. A turbine having a runner, a guide apparatus, annular flow guidingmeans for each said guide apparatus and said runner, said means in eachinstance comprising a nested pair of surfaces of revolution for limitingsaid annular flow and helical flow guiding surfaces having at least onethread arranged between said pair of said surfaces of revolution, meansfor causing an axial relative displacement between said guide apparatusand said runner and causing thereby a regulation of the proportion ofthe discharge sections between said runner flow guiding surfaces andthereby determining the entrance angle of flow into the runner, and anadditional control device provided in said guide apparatus and having acontrol face situated Within the flow-guiding surfaces thereof andadapted to aviod impact losses at the entrance of the runner.

4. A rotary pump having a runner, a discharge guide-apparatus annularflow guiding means for each of said runner and said guide apparatus,said means in each instance comprising a nested pair of surfaces ofrevolution for limiting said annular flow, and helical surfaces havingat least one thread arranged between said pair of said surfaces ofrevolution, means for causing a relative axial displacement between saidrunner and said discharge guide apparatus, a control edge provided onone of said surfaces of revolution of the discharge-guide apparatus andcausing a regulation of the discharge cross-section from said runnerupon said axial displacement, a further control edge provided on one ofsaid surfaces of revolution of the runner and causing a regulation ofthe cross-section of the zone of the discharge guide apparatus which isfree of helical guide surfaces, and a further device for control lingthe cross-section of the through-flow within the guide-apparatusprovided with the helical surfaces, said control causing the avoidanceof impact losses on the entrance of the discharge guide apparatus by areadjustment oi the angle of flow.

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